Air pump



FIG. 1 is a Perspective view of an air pump showing my new design;

FIG. 2 is a Front elevational view thereof;

FIG. 3 is a Rear elevational view thereof;

FIG. 4 is a Right side view thereof;

FIG. 5 is a Left side view thereof;

FIG. 6 is a Top plan view thereof; and,

FIG. 7 is a Bottom plan view thereof.

The broken lines in the drawing depict portions of the air pump that form no part of the claimed design. 

CLAIM The ornamental design for an air pump, as shown and described. 